Synthesis and Characterization of an Amphoteric Asphalt Emulsifier

Abstract A novel amphoteric asphalt emulsifier of octadecylbis(propanamide)-(3’-sodium phosphate-2’-hydroxypropyl)ammonium chloride was synthesised from the raw materials octadecylamine, acrylamide, epichlorohydrin and sodium dihydrogen phosphate. The tertiary amine octadecyl-bis(propanamide) was synthesised from octadecylamine and acrylamide (step 1). Sodium 3-chloro-2-hydroxypropyl phosphate (intermediate) was obtained from epichlorohydrin and sodium dihydrogen phosphate (step 2). The asphalt emulsifier was obtained from octadecyl-bis(propanamide)-tertiary amine and the intermediate by quaternisation reaction (step 3). The yield of the final product reached 94.90%. The structure was identified by FTIR, 1 H-NMR and elemental analysis. The critical micelle concentration of the product is 1.46 × 10 –5 mol L –1 . The surface tension at CMC is 37.78 mN ν –1 . The saturated adsorption amount of asphalt emulsifier is 2.72 × 10 –3 mmol ν –2 . The occupied area per asphalt emulsifier molecule at CMC is 0.611 nm 2 mol –1 . The surfactant is a fast-setting asphalt emulsifier.